Camera Pill Not as Good as Colonoscopy

Action Points

Explain that capsule endoscopy provided good images of the colon, although sensitivity was not as good as that of traditional colonoscopy.

Note, however, that sensitivity of capsule endoscopy increased as colon cleanliness improved.

Point out that the capsule has not been cleared for sale in the U.S. but is actively marketed in Europe and sold for $1,150.

LITTLE FALLS, N.J., July 15 -- A pill that contains an endoscope and two cameras provided good visualization of the colon, but had less sensitivity for detecting lesions than traditional colonoscopy, researchers say.

Sensitivity and specificity for detecting polyps that were 6 mm or larger were 64% and 84%, respectively, with capsule endoscopy, Andre Van Gossum, MD, of University Libre de Bruxelles in Belgium, and colleagues reported in the July 16 issue of the New England Journal of Medicine.

However, the sensitivity of the pill camera increased with the cleanliness of the colon, the researchers said.

"Efforts should be made," they said, "to improve the colon-preparation regimen for capsule endoscopy."

There's a need for a less invasive method of detecting lesions in the colon, the researchers said, especially one that would complement colonoscopy for those who've had an incomplete examination.

The PillCam capsule endoscope used in the study is an ingestible pill that consists of an endoscope with a video camera at both ends and measures 31 mm by 11 mm and has been proven safe in pilot studies.

To compare capsule endoscopy with optical colonoscopy, the researchers conducted a prospective, multicenter study, enrolling 328 patients with known or suspected colonic disease.

Different physicians interpreted the colonoscopy -- which was done for comparison -- and the capsule endoscopy.

Colon cleanliness was also assessed. Bowel preparation for capsule endoscopy was more extensive than typical colonoscopy because a residual clear liquid is needed to aid the capsule in its travel through the gastrointestinal tract.

So oral sodium phosphate and water were given two hours after ingestion of the pill, with an additional dose in the early afternoon.

The capsule was excreted within 10 hours of ingestion and before the end of the camera's battery lifetime in 92.8% of patients. Natural excretion was accomplished for all patients within 16 hours of ingestion.

Of 19 cancers detected by colonoscopy, 14 were also detected by capsule endoscopy (sensitivity 74%, 95% CI 52 to 88).

The researchers said that the sensitivity of capsule endoscopy was significantly higher in patients with good or excellent colon cleanliness than in those with poor or fair cleanliness, although cleanliness had only a limited effect on specificity.

Adverse events occurred in 7.9% of patients and were primarily related to colon preparation. They included abdominal discomfort, nausea, vomiting, and headache, but most were mild-to-moderate and resolved within 48 hours.

The researchers noted that the study sample was not representative of a typical screening population because the patients were known or suspected to have colonic disease.

"This study shows that capsule endoscopy is a safe method of visualizing the colonic mucosa through colon fluids without the need for sedation or insufflation," they said. "However, the sensitivity of capsule endoscopy for detecting colonic polyps, advanced adenomas, and colorectal cancer was relatively low in comparison with colonoscopy."

In an accompanying editorial, Michael Bretthauer, MD, PhD, of Oslo University Hospital, said that since the size of colorectal lesions is a predictor of the development of cancer, "the relatively low sensitivity of capsule endoscopy is cause for concern."

However, he said, "the sensitivity of both colonoscopy and CT colonography are better for the detection of large lesions than small lesions."

He stated that in light of the sensitivity, the requirement for more extensive bowel-cleansing regimens, and its high cost ($1,150), "colon capsule endoscopy cannot be recommended at this time."

He noted that detection rates for polyps and cancer are only surrogates for the ability to reduce associated mortality. All three procedures -- colonoscopy, CT colonography, and capsule endoscopy -- Dr. Bretthauer said, "should be tested in randomized, comparative trials that allow valid and precise quantification of their effect on colorectal cancer incidence and mortality."

The study was supported by Given Imaging, maker of the PillCam capsules.

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